commit 2972485a91007a12d3ad1c6057601ccbf15f01ef
author Greg Hackmann <ghackmann@google.com> Mon Jul 23 15:31:10 2012 -0700
committer Greg Hackmann <ghackmann@google.com> Tue Jul 24 10:01:51 2012 -0700
tree 531eba1b7d881625825e86e01ff369d8bc22d8f4
parent 3464b1dd35ad9c49f797e069922f22a788a8b440

hwc: read vsync timestamps from sysfs

Change-Id: Ife094105b247f4cfd2edb148a1914c50f62873b4
Signed-off-by: Greg Hackmann <ghackmann@google.com>

libhwc/hwc.cpp

diff --git a/libhwc/hwc.cpp b/libhwc/hwc.cpp
index 1dcd320..d948f38 100644
--- a/libhwc/hwc.cpp
+++ b/libhwc/hwc.cpp
@@ -16,6 +16,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <poll.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -72,6 +73,7 @@
     hwc_composer_device_1_t base;
 
     int                     fd;
+    int                     vsync_fd;
     exynos5_hwc_post_data_t bufs;
 
     const private_module_t  *gralloc_module;
@@ -708,27 +710,23 @@
         pdev->procs->invalidate(pdev->procs);
 }
 
-static void handle_vsync_uevent(struct exynos5_hwc_composer_device_1_t *pdev,
-        const char *buff, int len)
+static void handle_vsync_event(struct exynos5_hwc_composer_device_1_t *pdev)
 {
-    uint64_t timestamp = 0;
-    const char *s = buff;
-
     if (!pdev->procs || !pdev->procs->vsync)
         return;
 
-    s += strlen(s) + 1;
-
-    while (*s) {
-        if (!strncmp(s, "VSYNC=", strlen("VSYNC=")))
-            timestamp = strtoull(s + strlen("VSYNC="), NULL, 0);
-
-        s += strlen(s) + 1;
-        if (s - buff >= len)
-            break;
+    char buf[4096];
+    int err = read(pdev->vsync_fd, buf, sizeof(buf));
+    if (err < 0) {
+        ALOGE("error reading vsync timestamp: %s", strerror(errno));
+        return;
     }
+    buf[sizeof(buf) - 1] = '\0';
 
-    pdev->procs->vsync(pdev->procs, 0, timestamp);
+    errno = 0;
+    uint64_t timestamp = strtoull(buf, NULL, 0);
+    if (!errno)
+        pdev->procs->vsync(pdev->procs, 0, timestamp);
 }
 
 static void *hwc_vsync_thread(void *data)
@@ -741,19 +739,35 @@
     setpriority(PRIO_PROCESS, 0, HAL_PRIORITY_URGENT_DISPLAY);
 
     uevent_init();
+
+    struct pollfd fds[2];
+    fds[0].fd = pdev->vsync_fd;
+    fds[0].events = POLLPRI;
+    fds[1].fd = uevent_get_fd();
+    fds[1].events = POLLIN;
+
     while (true) {
-        int len = uevent_next_event(uevent_desc,
-                sizeof(uevent_desc) - 2);
+        int err = poll(fds, 2, -1);
 
-        bool vsync = !strcmp(uevent_desc,
-                "change@/devices/platform/exynos5-fb.1");
-        if (vsync)
-            handle_vsync_uevent(pdev, uevent_desc, len);
+        if (err > 0) {
+            if (fds[0].revents & POLLPRI) {
+                handle_vsync_event(pdev);
+            }
+            else if (fds[1].revents & POLLIN) {
+                int len = uevent_next_event(uevent_desc,
+                        sizeof(uevent_desc) - 2);
 
-        bool hdmi = !strcmp(uevent_desc,
-                "change@/devices/virtual/switch/hdmi");
-        if (hdmi)
-            handle_hdmi_uevent(pdev, uevent_desc, len);
+                bool hdmi = !strcmp(uevent_desc,
+                        "change@/devices/virtual/switch/hdmi");
+                if (hdmi)
+                    handle_hdmi_uevent(pdev, uevent_desc, len);
+            }
+        }
+        else if (err == -1) {
+            if (errno == EINTR)
+                break;
+            ALOGE("error in vsync thread: %s", strerror(errno));
+        }
     }
 
     return NULL;
@@ -809,6 +823,13 @@
         goto err_get_module;
     }
 
+    dev->vsync_fd = open("/sys/devices/platform/exynos5-fb.1/vsync", O_RDONLY);
+    if (dev->vsync_fd < 0) {
+        ALOGE("failed to open vsync attribute");
+        ret = dev->vsync_fd;
+        goto err_ioctl;
+    }
+
     sw_fd = open("/sys/class/switch/hdmi/state", O_RDONLY);
     if (sw_fd) {
         char val;
@@ -835,11 +856,13 @@
     if (ret) {
         ALOGE("failed to start vsync thread: %s", strerror(ret));
         ret = -ret;
-        goto err_ioctl;
+        goto err_vsync;
     }
 
     return 0;
 
+err_vsync:
+    close(dev->vsync_fd);
 err_ioctl:
     close(dev->fd);
 err_get_module:
@@ -851,6 +874,9 @@
 {
     struct exynos5_hwc_composer_device_1_t *dev =
             (struct exynos5_hwc_composer_device_1_t *)device;
+    pthread_kill(dev->vsync_thread, SIGTERM);
+    pthread_join(dev->vsync_thread, NULL);
+    close(dev->vsync_fd);
     close(dev->fd);
     return 0;
 }